Silane adduct, manufacturing thereof and method for coupling organic die attach adhesive and inorganic materials using the same

ABSTRACT

The present invention relates to silane adducts having a relatively higher adhesive strength as expressed formula X 3 SiR 1 , and manufacturing method thereof. wherein X is a hydrogenated form selected from one of epoxy compounds, amino compounds and bisphenolic, and R 1  is selected from one of glycidyloxypropyl group, 2-(3,4-epoxycyclohexyl)ethyl group, 3-acryloxypropyl group, 3-methacryloxypropyl group, amino-propyl group, 3-[2-(2-aminoethylamino)ethylamino]propyl group, N-methylaminopropyl group, N-phenylaminopropyl group, N,N-dimethyl-3-aminopropyl group, mercapto-propyl group, cyano-propyl group, and isocyanato-propyl group.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to silane adducts used as coupling agentswhich adhere inorganics like metal, glass or ceramic to organicadhesives like epoxy resin, polyimide resin, polyimide-siloxane resin,and siloxane resin used in the field of semiconductor package ofBoard-On-Chip (BOC), and Chip Scale Package (CSP) installed onelectronic devices, cellular phone and computers, etc. Morespecifically, the present invention relates to silane adducts having arelatively higher adhesive strength as expressed formula 1, andmanufacturing method thereof.

-   -   wherein X is a dehydrogenated form selected from one of epoxy        compounds, amino compounds, and bisphenolics, and R¹ is a        organoalkyl group, which is one of the functional group selected        among glycidyloxypropyl group,        2-(3,4-epoxycyclohexyl)ethyl-group, 3-acryloxypropyl group,        3-methacryloxypropyl group, amino-propyl group,        3-[2-(2-aminoethylamino)ethylamino]propyl group,        N-methylaminopropyl group, N-phenylaminopropyl group,        N,N-dimethyl-3-aminopropyl group, mercapto-propyl group,        cyano-propyl group, and isocyanato-propyl group.

2. Description of the Background Art

Conventional silane coupling agent as expressed formula 2 is used ascoupling agents which adhered inorganics like metal, glass or ceramic toorganic adhesives like epoxy resin, polyimide resin, polyimide-siloxaneresin, and siloxane resin used in the field of semiconductor package ofBoard-On-Chip (BOC), and Chip Scale Package (CSP) installed onelectronic devices, cellular phone, computer, semiconductor materiallike BOC, and CSP

wherein, R is methyl or ethyl group. R¹ is selected from one ofglycidyloxypropyl group, 2-(3,4-epoxycyclohexyl)ethyl group,3-acryloxypropyl group, 3-methacryloxypropyl group, amino-propyl group,3-[2-(2-aminoethylamino)ethylamino]propyl group, N-methylaminopropylgroup, N-phenylaminopropyl group, N,N-dimethyl-3-aminopropyl group,mercapto-propyl group, cyano-propyl group, and isocyanato-propyl group,which has a reactivity or a compatibility with polymeric materials.

More details, for the purpose that the silane coupling agent asexpressed formula 2 couples inorganic material to organic materials, theRO— group of the conventional silane coupling agent as expressed formula2 must be transformed into silanol group, —SiOH, as expressed formula 3by hydrolysis process as shown in reaction 1.

Silanol group of formula 3 formed by hydrolysis chemically reacted toinorganic materials, and R¹ group can be chemically coupled to otherorganic materials. From the reaction, the bond between organic adhesivesand inorganics will be strengthened.(RO)₃SiR¹+H₂O(HO)₃SiR¹+3R—OH  [Reaction 1]

wherein R and R¹ are the same as those of formula 2, and R—OH is organicby-product with low molecule. Because R—OH is a volatile organiccompound, it is desirable to minimize the by-product for safety andenvironmental cause.

In general, there are three methods of Solution, Dry-blend, and Integralblend to adapt the conventional silane compounds and then to bondbetween organic adhesive and inorganics. The details are shown below:

1) Solution Method:

It is used to make compounds of formula 3 with silanol group throughhydrolysis of RO— group as shown in reaction 1 by adding silane couplingagent to alcohol/water co-solvent. This process takes an hour and it isvery important to properly control pH of the solution.

2) Dry Blend Method:

It is a method that silane compounds without hydrolysis are directlyadded or silane compounds blended with solvent are added into mineralfillers, before impregnating the fillers to resin.

However, it has the disadvantage that the silane compound is notuniformly wetted over the filler.

3) Integral Blend Method:

This method is to directly add the silane coupling agent withouttreatment by hydrolysis to a polymeric phase etc. and then to diffusethe silane coupling agent on the surface of fillers uniformly dispersedin polymer resin. This method is used in the case that the above twomethods are difficult to adopt. Its result is, however, less effectivethan the above two methods 1) and 2) which are directly wetted onsurface of fillers.

In the case where the silane coupling agent is applied to the organicdie attach adhesive so that chips as inorganic material are connectedwith substrates as electrical path in Board-On-Chip (BOC) orChip-Scale-Package (CSP) of semiconductor, the solution method and thedry blend method can not be used because the surfaces of the chip andthe substrate cannot be directly treated with silane coupling agent. Forthat purpose, the integral blend method directly adding the silanecoupling agent to the adhesive should be used.

However, if the integral blend method is used in order that the generalsilane coupling agent is added into the adhesive applied to BOC or CSP,R—OH group generated by hydrolysis forms void on the interface betweenthe die attach adhesive and metal or chip. The void trapped on theinterface may give rise to incomplete wetting, which inevitably leads toa decrease of the adhesive strength when external thermal or mechanicalstress is applied thereto. Therefore, the adhesive with the conventionalsilane coupling agent is very difficult to use for adhesion of packagelike BOC and CSP for semiconductors.

SUMMARY OF THE INVENTION

Accordingly, in order to overcome the above problems and be applied toBoard-On-Chip (BOC) or Chip-Scale-Package (CSP), it is an objective ofthe present invention to provide a silane adduct with relatively higheradhesion strength and effective process, and void-free characteristicsas expressed formula 1, and manufacturing method thereof and method ofcoupling organic die attach adhesive with inorganic materials using thesame.

wherein, X is a dehydrogenated form selected from one of epoxycompounds, amino compounds and bisphenolics. Here, (a) the epoxycompounds above is selected one of diglycidyl ether of bisphenol A(Mn=380˜50,000), diglycidyl ether of bisphenol F (Mn=340˜4,000),phenol-novolac epoxy, o-cresol novolac epoxy, bisphenol A-novolac epoxyand diglycidyl terephtalate.

(b) The amino compounds is selected from one of imidazole, piperidine,dicyandiamide, 4,4,′-diaminodiphenylsulfone(DDS),4,4′-diaminodiphenylmethane (DDM), 4,4′-diaminodiphenylpropane,4,4′-oxydianiline, 1,4-cyclohexanediamine, hexamethylenediamine,heptamethylenediamine, nonamethylenediamine, decamethylenediamine,2,4-diaminotoluene, and 2,6-diaminotoluene.

(c) The bisphenolics is selected from one of 4,4′-isopropylidenediphenol, 4,4′-isopropylidenebis (2,6-dimethyl phenol),4,4′-ethylidenebisphenol, Bis(4-hydroxyphenyl)methane,4,4′-(1,3-phenylenediisopropylidene)bisphenol,4,4′-(1,4-phenylenedi-isopropylidene)bisphenol, 4,4′-Sulfonyldiphenol,4,4′-cyclohexylidene bisphenol, andbis(4-hydroxyphenyl)-2,2-dichloroethylene.

R¹ is a organoalkyl group, which is one of the functional group selectedamong glycidyloxypropyl group, 2-(3,4-epoxycyclohexyl)ethyl group,3-acryloxypropyl group, 3-methacryloxypropyl group, amino-propyl group,3-[2-(2-aminoethylamino)ethylamino]propyl group, N-methylaminopropylgroup, N-phenylaminopropyl group, N,N-dimethyl-3-aminopropyl group,mercapto-propyl group, cyano-propyl group, and isocyanato-propyl group.

The silane addcuct as expressed formula 1 can be synthesized throughreaction 2.(RO)₃SiR¹+3XX₃SiR¹+3R—OH  [reaction 2]

wherein, X is selected from one of epoxy compounds, amino compounds andbisphenolics. Here, (a) the epoxy compounds above is selected one ofdiglycidyl ether of bisphenol A (Mn=380˜50,000), diglycidyl ether ofbisphenol F (Mn=340˜4,000), phenol-novolac epoxy, o-cresol novolacepoxy, bisphenol A-novolac epoxy and diglycidyl terephtalate.

(b) The amino compounds is selected from one of imidazole, piperidine,dicyandiamide, 4,4,′-diaminodiphenylsulfone(DDS),4,4′-diaminodiphenylmethane (DDM), 4,4′-diaminodiphenylpropane,4,4′-oxydianiline, 1,4-cyclohexanediamine, hexamethylenediamine,heptamethylenediamine, nonamethylenediamine, decamethylenediamine,2,4-diaminotoluene, and 2,6-diaminotoluene.

(c) The bisphenolics is selected from one of 4,4′-isopropylidenediphenol, 4,4′-isopropylidenebis (2,6-dimethyl phenol),4,4′-ethylidenebisphenol, Bis(4-hydroxyphenyl)methane,4,4′-(1,3-phenylenediisopropylidene)bisphenol,4,4′-(1,4-phenylenedi-isopropylidene)bisphenol, 4,4′-Sulfonyldiphenol,4,4′-cyclohexylidene bisphenol, andbis(4-hydroxyphenyl)-2,2-dichloroethylene.

Wherein R and R¹ are the same as those of formula 1.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a reactor for forming the silaneadduct according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The detailed explanation of the silane adduct according the presentinvention and the manufacturing method thereof as follows:

First of all, the silane adduct of the present invention is expressed byformula

wherein, X is a dehydrogenated form selected from one of epoxycompounds, amino compounds and bisphenolics.

(a) The epoxy compounds is selected from one of diglycidyl ether ofbisphenol A (Mn=380˜50,000), diglycidyl ether of bisphenol F(Mn=340˜4,000), phenol-novolac epoxy, o-cresol novolac epoxy, bisphenolA-novolac epoxy and diglycidyl terephtalate.

(b) The amino compounds is selected from one of imidazole, piperidine,dicyandiamide, 4,4,′-diaminodiphenylsulfone(DDS),4,4′-diaminodiphenylmethane (DDM), 4,4′-diaminodiphenylpropane,4,4′-oxydianiline, 1,4-cyclohexanediamine, hexamethylenediamine,heptamethylenediamine, nonamethylenediamine, decamethylenediamine,2,4-diaminotoluene, and 2,6-diaminotoluene.

(c) The bisphenolics is selected from one of 4,4′-isopropylidenediphenol, 4,4′-isopropylidenebis (2,6-dimethyl phenol),4,4′-ethylidenebisphenol, Bis(4-hydroxyphenyl)methane,4,4′-(1,3-phenylenediisopropylidene)bisphenol,4,4′-(1,4-phenylenedi-isopropylidene)bisphenol, 4,4′-Sulfonyidiphenol,4,4′-cyclohexylidene bisphenol, andbis(4-hydroxyphenyl)-2,2-dichloroethylene.

R¹ is selected from one of glycidyloxypropyl group,2-(3,4-epoxycyclohexyl)ethyl group, 3-acryloxypropyl group,3-methacryloxypropyl group, amino-propyl group,3-[2-(2-aminoethylamino)ethylamino]propyl group, N-methylaminopropylgroup, N-phenylaminopropyl group, N,N-dimethyl-3-aminopropyl group,mercapto-propyl group, cyano-propyl group, and isocyanato-propyl group.

The X group is physically adsorbed or chemically reacted to theinorganic materials and the R¹ group is chemically coupled to otherorganic compounds, thereby the organic adhesive and inorganic materialsare coupled each other.

In the silane adduct of the present invention, RO group of theconventional silane coupling agent is replaced with X group. Therefore,the silane adduct of present invention can couple to the inorganicmaterials without hydrolysis. Also, since it can directly apply to anorganic adhesive used in the electrical materials, it does not cause anyboundary surface void. In contrast, in the prior art, the boundarysurface void was essentially generated by lower molecule, R—OH, formedby hydrolysis process of the conventional silane coupling agent. Inother words, the present invention does not need the hydrolysis processfor the silane adduct, and does not generate the lower moleculematerials not functioning adhesive reaction and rather degrading theboundary surface characteristics. Instead, the silane adduct of thepresent invention has a characteristics of relatively higher adhesion.

Next, the manufacturing method of the silane adduct mentioned above willbe explained below.

The silane addcuct as expressed formula 1 can be synthesized throughreaction 2.(RO)₃SiR¹+3XX₃SiR¹+3R—OH  [reaction 2]

wherein, X is selected from one of epoxy compounds, amino compounds andbisphenolics. Here, (a) the epoxy compounds above is selected one ofdiglycidyl ether of bisphenol A (Mn=380˜50,000), diglycidyl ether ofbisphenol F (Mn=340˜4,000), phenol-novolac epoxy, o-cresol novolacepoxy, bisphenol A-novolac epoxy and diglycidyl terephtalate.

(b) The amino compounds is selected from one of imidazole, piperidine,dicyandiamide, 4,4,′-diaminodiphenylsulfone(DDS),4,4′-diaminodiphenylmethane (DDM), 4,4′-diaminodiphenylpropane,4,4′-oxydianiline, 1,4-cyclohexanediamine, hexamethylenediamine,heptamethylenediamine, nonamethylenediamine, decamethylenediamine,2,4-diaminotoluene, and 2,6-diaminotoluene.

(c) The bisphenolics is selected from one of 4,4′-isopropylidenediphenol, 4,4′-isopropylidenebis (2,6-dimethyl phenol),4,4′-ethylidenebisphenol, Bis(4-hydroxyphenyl)methane,4,4′-(1,3-phenylenediisopropylidene)bisphenol,4,4′-(1,4-phenylenedi-isopropylidene)bisphenol, 4,4′-Sulfonyldiphenol,4,4′-cyclohexylidene bisphenol, andbis(4-hydroxyphenyl)-2,2-dichloroethylene.

Wherein R and R¹ are the same as those of formula 1.

More details, in the reactor as shown in FIG. 1, organic material X of50˜500 weight %, triphenylphospine of 0.1˜5 weight %, and the silanecoupling agent of 10˜100weight % as expressed formula 2 are added to asolvent of 200˜5000 ml which is selected from one of water/ethanolco-solvent of 5:95 to 20:80 weight %, ethanol, toluene, n-hexane,methylene chloride, chloroform, trichloroethan, tetrachloroethane,N,N-dimethylformamide(DMF), N,N-dimethylacetamide(DMAc), and dimethylsulfoxide(DMSO), and to react each other, thereby producing the silaneadduct. Then, it is reacted in a bath maintaining its temperature50˜200° C. for 2˜8 hours as mixed by a stirrer rotating with 100˜500rpm.

In the case that water/ethanol or ethanol is chosen as a solvent, it isdesirable that an acetate acid of 0.01˜0.5 weight % to 100 weight %solvent is added thereto.

Further, during reaction, the loss of solvent is minimized by reflux anda by-product like alcohols is continuously removed therefrom. Therefore,from the removal process of alcohol, the substitution reaction of RO toX group can be irreversibly maintained. After finishing the reaction,the solvent and remnant non-reacted substances are removed by a vacuummethod.

In reactor shown in FIG. 1, number 1 among components is a condenser and1—1 is an inlet line of water, 1-2 is an outlet line, 3-1 is an injectline of reactants, 3-2 is a line for vacuum, 4 is an impeller forstirring and 5 is a thermometer.

[Embodiment 1]

Adding 4,4′-isopropylidene diphenol (bisphenol A) of 30 g,(3-Aminopropyl)trimethoxysilane of 10 g, triphenylphosphine of 0.1 g totrichloroethane solution of 200 ml in the reactor dipped into the bath,which is maintained the temperature of 95° C.; reacting each othertherein for two hours; cooling the solution under 50° C.; and removingremaining trichloroethane solution therefrom by a vacuum method.

[Embodiment 2]

Adding 4,4′-isopropylidene diphenol (bisphenol A) of 30 g,(glycidyloxy)trimethoxysilane of 10 g, triphenylphosphine of 0.1 g totrichloroethane solution of 200 ml in the reactor dipped into the bath,which is maintained the temperature of 95° C.; reacting each othertherein for two hours; Cooling the solution under 50° C.; and removingremaining trichloroethane solution therefrom by a vacuum method.

[Experimental Embodiment]

The next experiment is tested for comparing the adhesion strength of thesilane adduct of the present invention with that of the conventionalsilane coupling agent as shown below.

The comparison is that: cases of adding 1 g of the adducts producedrespectively in embodiment 1 and embodiment 2 to a diglycidylether-Bisphenol A of 100 g, and cases of adding the unmodified form of(3-aminopropyl)trimethoxysilane, and (3-glycidyloxy)trimethoxysilanerespectively to the same type of the epoxy above as a reference.

Commonly the formulation of the used adhesive has the following recipe:

DGEBA epoxy (Mn = 380, Kukdo chemical) 50 g DGEBA epoxy (Mn = 975, Kukdochemical) 50 g Dicyandiamide (DICY, Aldrich)  4 g Carboxyl terminatedbutadiene acrylonitrile copolymer 10 g (CTBN-13, BF Goodrich) ModifiedSilane compound (Silane adduct)  1 g

After mixed each epoxy at 80° C. for 30 minutes, CTBN13 rubber is addedthereto. Then, they are stirred for uniformly mixing with 200 rpm for 30minutes, respectively. Next DICY and modified silane are injectedthereto and at the same time they are stirred with 200 rpm for 30minutes at 120° C. At the same time, bubbles generated during thereaction are removed therefrom by applying vacuum thereto. After that, asolution is coated on the substrates, electrolytic copper foil substrate(thickness=35 μm) and Upilex-S PI (thickness=50 μm) of organicmaterials, respectively, with the adhesive thickness of 50 μm by adoctor blade. After coating, the coated materials are cured at 175° C.for 1 hour and then compared their adhesion forces therewith. Here, thetest for the adhesion force was adopted to ASTM D1876-72.

TABLE 1 Peel strength (g/cm) Code Material Cu foil Upilex S S1(3-aminopropyl)trimethoxysilane 1220 810 S2(glycidyloxy)trimethoxysilane 1050 740 MS1 Modified silane(Embodiment 1) 1840 1200 MS2 Modified silane (Embodiment 2) 1530 1120

TABLE 2 Comparative peel strength Cu foil Upilex S MS1/S1 1.58* 1.48MS2/S2 1.46 1.51 *The value of more than 1 means that the modifiedsilane is more effective to unmodified one.

Here, S1 and S2 stand for unmodified silanes in comparison embodiments 1and 2, and MS1 and MS2 denote modified silanes in embodiments 1 and 2,respectively.

As shown in tables 1 and 2, the ratio of adhesion strength from thenewly modified silane adducts in present invention (MS1, MS2) to that ofunmodified silane couping agent (S1, S2) is greater than 1, morespecifically 1.46. These results show that the adhesion strength of themodified silane adduct is higher than that of the unmodified silaneadduct with respect to electrolytic copper foil as metal materials andPI as organic materials.

Therefore, the silane adduct of the present invention can effectivelystrengthen bonding between the inorganic materials and organic materialswhen compared with silane coupling agent of the prior art.

Moreover, the silane adduct of the present invention does not affect anyenvironment problem since it does not produce low molecules notfunctioning adhesion. Also, when using as a component in an adhesive,since the silane adduct of the present invention does not produce anybubbles at the boundary surface between adherend, and thereby not causeany corrosion or weak boundary thereon, it can be applied to adherevarious organic-inorganic materials.

1. A silane adduct as expressed formula below,

wherein, X is a dehydrogenated form selected from the group consistingof epoxy compounds, amino compounds and bisphenolics; and R¹ is aorganoalkyl group, which is one of the functional group selected fromthe group consisting of glycidyloxypropyl group,2-(3,4-epoxycyclohexyl)ethyl group, 3-acryloxypropyl group,3-methacryloxypropyl group, amino-propyl group,3-[2-(2-aminoethylamino)ethylamino]propyl group, N-methylaminopropylgroup, N-phenylaminopropyl group, N,N-dimethyl-3-aminopropyl group,mercapto-propyl group, cyano-propyl group, and isocyanato-propyl group.2. The silane adduct according to claim 1, wherein the epoxy compound isselected from one of diglycidyl ether of bisphenol A (Mn=380˜50,000),diglycidyl ether of bisphenol F (Mn=340˜4,000), phenol-novolac epoxy,o-cresol novolac epoxy, bisphenol A-novolac epoxy, and diglycidylterephtalate.
 3. The silane adduct according to claim 1, wherein theamino compound is selected from one of imidazole, piperidine,dicyandiamide, 4,4,′-diaminodiphenylsulfone(DDS),4,4′-diaminodiphenylmethane(DDM), 4,4′-diaminodiphenylpropane,4,4′-oxydianiline, 1,4-cyclohexanediamine, hexamethylenediamine,heptamethylenediamine, nonamethylenediamine, decamethylenediamine,2,4-diaminotoluene, and 2,6-diaminotoluene.
 4. The silane adductaccording to claim 1, wherein the bisphenolics is selected from one of4,4′-isopropylidene diphenol, 4,4′-isopropylidenebis(2,6-dimethylphenol), 4,4′-ethylidenebisphenol, Bis(4-hydroxyphenyl)methane,4,4′-(1,3-phenylenediisopropylidene)bisphenol,4,4′-(1,4-phenylenedi-isopropylidene)bisphenol, 4,4′-Sulfonyldiphenol,4,4′-cyclohexylidene bisphenol, andbis(4-hydroxyphenyl)-2,2-dichloroethylene.